<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <div id="root"></div>
</body>

</html>
<script src="https://unpkg.com/vue@next"></script>
<script>
    const app = Vue.createApp({
        methods:{
            handleChange(){
                alert('change')
            }
        },
        template: `
        <child @change="handleChange">parent</child>
        `,
    })
    app.component('child',{
        template:`<div @click="handleClick">123123</div>`,
        setup(props, context) {
            const {h} =Vue;
            const {attrs,slots,emit}=context
            function handleClick(){
                emit('change')
            }
            return {handleClick}
        }
    })
    const vm = app.mount('#root')
</script>